AM5726: GPMC throughput

David Tu

Part Number: AM5726

Hello,

My name is David Tu from Tensorcom. We are dedicate 60GHz Wireless Fabless company. We have our MP for our first Generation 60GHz SoC (RF+BB) ready. We have have customer inquiries to use AM5726 as network processor, which provide GPMC interface. Our SoC also provide GPMC interface as well. With our current GPMC interface to Cypress FX3 GPIF (programmable interface) we can have 1 Gbps. Have TI test what's maximum speed on GPMC interface? We need this network processor to be part of our design. I'm looking forward to get your feedback.

David Tu

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

For AM572x maximum GPMC clock frequency in synchronous mode is 88.5MHz. The interface is 16-bit wide. Calculated roughly, the GPMC would need 5-7 clock cycles to setup address and then burst is 1 cycle per word. Maximum burst length is 16 x 32 bit words on the internal interconnect.

This would make at best 5 + 32 GPMC clock cycles for a 512 bit transfer, or roughly 13 bits per clock cycle, so throughput will be 13 * 88.5MHz = 1.15Gbps at best.

You should understand that these are very rough calculations and actual performance will be less than that.

0 David Tu over 8 years ago in reply to Biser Gatchev-XID

Prodigy 40 points

Does it mean every burst need to have software involved? What's the time for firmware to setup one burst? does it need firmware to involve to setup each burst? is there a way the burst automatically repeat itself until transmit 4K bytes. We can only do 200 Mbps as test. We can have 1.3 Gbps with Cypress on 100MHz BUS speed.

0 Biser Gatchev-XID over 8 years ago in reply to David Tu

TI__Guru**** 393215 points

I have asked the software team to comment. They will respond here.

0 David Tu over 8 years ago in reply to Biser Gatchev-XID

Prodigy 40 points

Do you have update for the question?

0 Steve Kipisz over 8 years ago in reply to David Tu

TI__Genius 15510 points

I am looking at this.

Steve K.

0 JJD over 8 years ago in reply to Steve Kipisz

TI__Guru* 89485 points

David, you should be able to setup DMAs to request blocks of data across the GPMC bus, so software does not have to get involved in the transfer except for initial configuration of the DMA. Then you can configure the GPMC for burst mode, and use ATTACHEDDEVICEPAGELENGTH to specify the burst length of each transaction to maximize the bus utilization.

Regards,

James

0 David Tu over 8 years ago in reply to JJD

Prodigy 40 points

Hello JJD,

Do you have test result base on this configuration?

Thank you

Regards,

David Tu

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AM5726: GPMC throughput